In a wireless network, the quality of the service is an important factor of user satisfaction. Due to the limited nature of the wireless spectrum, it is necessary to increase base station density in order to increase net throughput per user. In such an environment, automatic traffic congestion and avoidance and the self-healing nature of the wireless network become increasingly important.
Many techniques exist for avoiding interference on a single wireless link by preventing that different mobile terminals corrupt each other's transmitted signal by transmitting at the same time (TDMA, FDMA, CDMA, OFDMA, CSMA). In addition, directed links can be utilized, preventing the mobile stations from causing mutual interference.
However, these techniques lose their effectiveness if the number of mobile stations that wish to speak to the same base station at the same time increases over a certain threshold. Thus, to assure a satisfactory level of Quality of Service, the network is divided into geographically separate segments or cells, each being served by its own base station, which serve geographically localized mobile stations only.
To maximize net throughput per user, an operator must utilize a larger number of smaller cells, each serving a smaller number of mobile stations with higher net throughput per user. For that reason, the segments of 4G networks are much smaller than cells in traditional cellular networks and are consequently termed pico cells. Each pico cell is served by a pico base station.
In a network, covered by a high number of densely distributed base stations with partially or completely overlapping cells, it is crucial to automate the network operation and management. An important aspect of network management is congestion avoidance, which assures that no single base station is overloaded if there is available transmission capacity available that could be used to offload the congested base station. However, such high density of 4G networks at the same time increases the amount of handover events, where mobile station switches from one base station to the next.
The present invention describes a method for measuring relative committed traffic rate and air interface utilization, and on the basis of thus obtained results manages the base station neighbor lists, which are used by mobile terminals for base station selection.
Other similar inventions exist, such as US2007/0293235.